1. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 1 FIGURE 18–1 Maximum braking traction occurs when tire slip is between 10% and 20%. A rotating tire has 0% slip and a locked-up wheel has 100% slip.

2. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 2 FIGURE 18–2 Traction is determined by pavement conditions and tire slip.

3. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 3 FIGURE 18–3 A good driver can control tire slip more accurately than an ABS if the vehicle is traveling on a smooth, dry road surface.

4. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 4 FIGURE 18–4 A wedge of gravel or snow in the front of a locked wheel can help stop a vehicle faster than would occur if the wheel brakes were pulsed on and off by an antilock braking system.

5. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 5 FIGURE 18–5 Being able to steer and control the vehicle during rapid braking is one major advantage of an antilock bracking system.

6. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 6 FIGURE 18–6 A typical stop on a slippery road surface without antilock brakes. Notice that the wheels stopped rotating and skidded until the vehicle finally came to a stop.

7. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 7 FIGURE 18–7 ABS configuration includes four-channel, three-channel, and single-channel.

8. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 8 FIGURE 18–8 A typical inlegral ABS unit that combines the function of the master cylinder, brake booster, and antilock braking system in one assembly.

9. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 9 FIGURE 18–9 A typical nonintegral-type (remote) ABS.

10. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 10 FIGURE 18–10 A schematic drawing of a typical antilock braking system.

11. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 11 FIGURE 18–11 Wheel speed sensors for the rear wheels may be located on the rear axle, on the transmission, or on the individual wheel knuckle.

12. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 12 FIGURE 18–12 A schematic of a typical wheel speed sensor.

13. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 13 FIGURE 18–13 Wheel speed sensors produce an alternating current (AC) signal with a frequency that varies in proportion to wheel speed.

14. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 14 FIGURE 18–14 A digital wheel speed sensor produces a square wave output siignal.

15. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 15 FIGURE 18–15 Typical inputs and outputs for brake control modules.

16. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 16 FIGURE 18–16 An ABS three-way solenoid can increase, maintain, or decrease brake pressure to a given brake circuit.

17. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 17 FIGURE 18–17 The isolation or hold phase of an ABS on a Bosch 2 system.

18. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 18 FIGURE 18–18 During the pressure reduction stage, pressure is vented from the brake circuit so the tire can speed up and regain traction.

19. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 19 FIGURE 18–19 The control module reapplies pressure to the affected brake circuit once the tire achieves traction so that normal braking can continue.

20. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 20 FIGURE 18–20 An integral ABS unit with a pump motor to provide power assist during all phases of braking and brake pressure during ABS stops.

21. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 21 WHEEL SPEED SENSOR

22. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 22 WHEEL SPEED SENSOR

23. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 23 WHEEL SPEED SENSOR

24. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 24 WHEEL SPEED SENSOR

25. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 25 WHEEL SPEED SENSOR

26. Automotive Chassis Systems, 5/e By James D. Halderman Copyright © 2010, 2008, 2004, 2000, 1995 Pearson Education, Inc., Upper Saddle River, NJ 07458 All rights reserved. 26 WHEEL SPEED SENSOR